Multi-Channel Bioimpedance System for Detecting Vascular Tone in Human Limbs: An Approach

Vascular tone plays a vital role in regulating blood pressure and coronary circulation, and it determines the peripheral vascular resistance. Vascular tone is dually regulated by the perivascular nerves and the cells in the inside lining of blood vessels (endothelial cells). Only a few methods for measuring vascular tone are available. Because of this, determining vascular tone in different arteries of the human body and monitoring tone changes is a vital challenge. This work presents an approach for determining vascular tone in human extremities based on multi-channel bioimpedance measurements. Detailed steps for processing the bioimpedance signals and extracting the main parameters from them have been presented. A graphical interface has been designed and implemented to display the vascular tone type in all channels with the phase of breathing during each cardiac cycle. This study is a key step towards understanding the way vascular tone changes in the extremities and how the nervous system regulates these changes. Future studies based on records of healthy and diseased people will contribute to increasing the possibility of early diagnosis of cardiovascular diseases.

Coronary Angiographyic Findings in Patients of Acute Coronary Syndrome with Atrial Fibrillation

Background: Acute coronary syndrome (ACS) is a fatal entity and can be even more deadly if they develops concomitant complications in the form of arrhythmias like atrial fibrillation. Coronary artery disease is thought to be more severe in cases with ACS and atrial fibrillation. Objective: To determine the angiographic findings in patients presenting with acute coronary syndrome and atrial fibrillation and To find the involvement of more common circulation (right or left coronary circulation) leading to atrial fibrillation in acute coronary syndrome. Materials and Methods: This 6 month case series study conducted at department of Cardiology, Sheikh Zayed Hospital, Rahim Yar Khan from14-01-20 to 14-09-20. A total of 198 cases aged 30-60 years of both gender were included in the study through non-probability consecutive sampling. Patients suffering with ACS and has atrial fibrillation on presentation or develops within 24 hours of admission were included. They underwent coronary angiography to look for number of vessels involved, severity of coronary artery disease and culprit vessel involved. Results: In this study there were total 198 cases. Mean age of the participants was 50.09±5.88 years and mean duration of atrial fibrillation was 14.91± 4.51 hours. There were 70 (35.35%) cases with DM, 78 (39.39%) with HTN and 61 (30.81%) smokers. STEMI was found in 35 (17.68%) and NSTEMI in 152 (76.77%) of cases as in figure 05. One vessel disease was observed in 26 (13.13%), two vessel disease in 147 (74.24%) and three vessel disease in 25 (12.63%) of cases. Mild disease on angiography was seen in 45 (22.73%), moderate in 132 (66.67%) and severe in 21 (10.61%) of the cases.it was found that out of 198 patients , 146 ( 74 %) had right coronary artery culprit lesion and 51 ( 26 %) has left sided coronary circulation culprit lesion and from left coronary circulation, left circumflex was most commonly involved : 41 ( 21 % ) of patients as compared to only 10 ( 5 %) patients had culprit in left anterior descending artery. Conclusion: AF in patients with ACS is most commonly associated with right coronary artery lesionsand right type of coronary circulation. In terms of number and severity of disease the most common pattern observed was two vessel disease comprising almost 3/4th of all cases and moderate disease was in most of the vesselsrespectively. Key words: ACS, Atrial fibrillation

Definitions and Epidemiology of Coronary Functional Abnormalities

Coronary functional abnormalities are frequent causes of angina pectoris, particularly in patients with unobstructed coronary arteries. There is a spectrum of endotypes of functional coronary abnormalities with different mechanisms of pathology including enhanced vasoconstriction (i.e. coronary artery spasm) or impaired vasodilatation, such as impaired coronary flow reserve or increased microvascular resistance. These vasomotor abnormalities can affect various compartments of the coronary circulation such as the epicardial conduit arteries and/or the coronary microcirculation. Unequivocal categorisation and nomenclature of the broad spectrum of disease endotypes is crucial both in clinical practice as well as in clinical trials. This article describes the definitions of coronary functional abnormalities with currently accepted cut-off values, as well as diagnostic methods to identify and distinguish endotypes. The authors also provide a summary of contemporary data on the prevalence of the different endotypes of coronary functional abnormalities and their coexistence.

Coronary vasodilation mediated by T cells expressing choline acetyltransferase

This study shows ChAT-expressing T cells can induce vasodilation of the blood vessel in the coronary circulation and that this effect relies on a direct interaction between T cells and the coronary vascular endothelium. The study establishes a potential immunomodulatory role for T cells in the coronary circulation. The present findings offer an additional possibility that a deficiency of ChAT-expressing T cells could contribute to reduced coronary blood flow and ischemic events in the myocardium.

To the assessment of changes in the electrocardiogram in coronary insufficiency

In the literature there are a number of reports on the effect of physical activity on the coronary circulation, but we did not find any works on the effect of a regimen with restriction of muscle movements on the ECG of patients with coronary insufficiency. This article reports the results of research on this issue. In addition, ECG changes were studied in patients in the subacute stage of myocardial infarction under the influence of walking.

Coronary venous therapy to improve microvascular dysfunction

The coronary circulation is a complex system in which vascular resistances are determined by an interplay of forces in at least three compartments: the epicardial, the microvascular, and the venous district. Cardiologists, and particularly interventional cardiologists, normallly place the focus of their attention on diseases of the epicardial coronary circulation as possible causes of coronary syndromes and neglect the importance of the other two compartments of coronary circulation. The study of the coronary microcirculation, an increasingly recognized source of ischemia, has long been disregarded, but is witnessing a revival since the (re-)introduction of diagnostic tools in the better equipped catheterization laboratories. Unfortunately, to date our understanding of coronary microvascular disease remains incomplete and the numerous proposed classifications fail to reflect its complexity. Further, no specific therapy for these disorders is available. The coronary venous circulation is an even more neglected third vascular district. Its role in regulating coronary resistances is almost completely unexplored, but inital evidence suggests that the modulation of venous pressure might help improve coronary perfusion. Coronary sinus interventions are a group of invasive techniques (both surgical and catheter-based) that are designed to treat ischaemic heart disease by increasing coronary venous pressure and therefore redistributing coronary blood flow towards the endocardium. In this review paper, we revise the role of these interventions with particular focus on acute and chronic coronary microvascular disease.

Some Anatomical Variations of the Coronary Circulation among Sri Lankan Adults

The coronary circulation has been the centre of focus of many anatomists, pathologists, cardiologists, cardiothoracic surgeons, physiologists and even the general public especially since the introduction of coronary angiography during the 1960's. Though a large number of data regarding the coronary circulation of the Western populations are available, research about coronary circulation of the Sri Lankan population is comparatively rare. This study comprises of data from 150 autopsy specimens of adult Sri Lankans died due to non-cardiac causes. 99.3% had a tricuspid aortic valve while only in 0.7% the aortic valve was bi-cuspid. The incidence of the ectopic origin of the left and the right coronary artery was equal (1.3%), and the posterior sinus was devoid of coronary ostia. A 55.3% of the study population had a single coronary artery ostium for each main coronary artery. The corresponding figure for the left coronary artery was 91.3%. Six percent (06%) of the right coronary ostia were positioned significantly above the sinus while the corresponding figure for the left coronary ostia was higher (17.5%). The average left ventricular wall thickness for males and females were 13mm and 12mm respectively. Significant muscular bridging (in relation to at-least one coronary artery) was found in 19.3% of the study population. The study concludes that variations in the cardiac anatomy are commoner than expected. As per Kitzman chart, cardiac dimensions of the Sri Lankans are somewhat smaller compared to the dimensions of the Western populations.

Wide-ranging clinical spectrum of paradoxical embolism

The purpose of this review is to raise the index of suspicion for paradoxical embolism among generalists. The review is based solely on anecdotal reports compiled from EMBASE, MEDLINE, Googlescholar and Pubmed. Search terms were ‘paradoxical embolism’, ‘pulmonary embolism’ and ‘pulmonary arteriovenous malformations’. What emerged was that right-to-left paradoxical embolism could occur with or without concurrent pulmonary embolism, and also with and without proof of the presence of an ‘embolus-in-transit’. Potential sites of single or multiple systemic involvement included the central nervous system, the coronary circulation, renal arterial circulation, splenic circulation, the mesenteric circulation and the limbs. In many cases, the deep veins of the lower limbs were the source of thromboembolism. In other cases, thrombi originated from an atrial septal aneurysm, from a central venous line, from a haemodialysis-related arterio-venous shunt, from a popliteal vein aneurysm, internal jugular vein, superior vena cava, from a pulmonary arteriovenous malformation, from tricuspid valve endocarditis (with and without pulmonary embolism) and from the right atrium, respectively. Stroke was by far the commonest systemic manifestation of paradoxical embolism. Some strokes were attributable to pulmonary arteriovenous malformations with or without coexistence of intracardiac shunts. Clinicians should have a high index of suspicion for paradoxical embolism because of its time-sensitive dimension when it occurs in the context of involvement of the intracranial circulation, coronary circulation, mesenteric circulation, and peripheral limb circulation.

Endothelial glycocalyx during early reperfusion in patients undergoing cardiac surgery

Background Experimental cardiac ischemia-reperfusion injury causes degradation of the glycocalyx and coronary washout of its components syndecan-1 and heparan sulfate. Systemic elevation of syndecan-1 and heparan sulfate is well described in cardiac surgery. Still, the events during immediate reperfusion after aortic declamping are unknown both in the systemic and in the coronary circulation. Methods In thirty patients undergoing aortic valve replacement, arterial concentrations of syndecan-1 and heparan sulfate were measured immediately before and at one, five and ten minutes after aortic declamping (reperfusion). Parallel blood samples were drawn from the coronary sinus to calculate trans-coronary gradients (coronary sinus–artery). Results Compared with immediately before aortic declamping, arterial syndecan-1 increased by 18% [253.8 (151.6–372.0) ng/ml vs. 299.1 (172.0–713.7) ng/ml, p < 0.001] but arterial heparan sulfate decreased by 14% [148.1 (135.7–161.7) ng/ml vs. 128.0 (119.0–138.2) ng/ml, p < 0.001] at one minute after aortic declamping. There was no coronary washout of syndecan-1 or heparan sulfate during reperfusion. On the contrary, trans-coronary sequestration of syndecan-1 occurred at five [-12.96 ng/ml (-36.38–5.15), p = 0.007] and at ten minutes [-12.37 ng/ml (-31.80–6.62), p = 0.049] after reperfusion. Conclusions Aortic declamping resulted in extracardiac syndecan-1 release and extracardiac heparan sulfate sequestration. Syndecan-1 was sequestered in the coronary circulation during early reperfusion. Glycocalyx has been shown to degrade during cardiac surgery. Besides degradation, glycocalyx has propensity for regeneration. The present results of syndecan-1 and heparan sulfate sequestration may reflect endogenous restoration of the damaged glycocalyx in open heart surgery.